Hair clips formed from two members having dual prongs normally urged together by a spring mechanism, providing a moment about a pivot means, and separable by application of pressure to handles on the side of the pivot means opposite the prongs of the members are generally known to the art. It is also known to strike from these members both resilient portions to serve as spring means and interconnecting portions to provide for attachment of the two members comprising the clip and to give the clip structural rigidity. For some of the prior art devices, a single means serves both functions, that is as a spring means and a connecting means. However, the hair clips heretofore known to the art suffer from several disadvantages which detract from their ease of fabrication and functional operability.
In fabricating the clip members from rolled sheet metal, it is desirable to form the members so that the clip may also be automatically assembled from the two members as part of the fabrication process. To facilitate such assembly it is necessary that the grain structures of the metal (the grains being elongated due to prior rolling operations) from which the clip members are formed run in identical directions in the finished assembly. In prior art hair clips such as the type disclosed in U.S. Pat. No. 3,101,725, the configuration of the leaf spring and prongs which hold the members together (not to be confused with the forward hair-grasping prongs) is such that to avoid fracture along elongated grain boundaries during formation of the prongs and leaf spring and during continued operation of the clip, the grain structure of the two members comprising the clip must run in opposite directions. Thus, if the two members are to be stamped from a single piece of sheet metal, one of the members must be reversed in space before the two members can be assembled. This prevents the hair clips from being assembled in a single automatic process.
The connecting and spring members of prior art devices also protrude above the outer surfaces of the assembled clip and tend to snag on the hair of the user. The outer dimensions of prior art hair clips are also generally asymmetrical with the handle portion of one of the members comprising the clip being turned at a relatively large angle to compensate for the relative flatness of the other member's handle and the lack of distance between the clip portions of the two members at their pivot point in order to achieve sufficient arc movement of the handle to adequately open the clip. The sharply out-turned handle portions of such clips and the portions which project beyond the outer surfaces of the clips often tend to cause discomfort to the user as for example when sleeping with the clips in place in the user's hair.
Further, the opening and closing action of prior art clips has been found to be generally stiff and often rough and uneven. The lateral rigidity of prior art clips, i.e., when forces are applied tending to laterally or angularly displace the two members in a horizontal plane substantially parallel to the surfaces of the clip, is also less than desirable since the prongs holding such clips together are generally of limited dimension in a direction along the longitudinal axis of the clips and hence have little resistance to rotation of one member relative to the other in the horizontal plane.